Self-adjustable backrest device

ABSTRACT

The self-adjustable backrest device supplements a seat surface such that said seat surface is a previously existing one and what is covered by the object of this invention adds a backrest or improves the existing one, for which purpose it comprises a mobile plate on which the user rests, wherein said plate swivels on a horizontal shaft that passes through a first set of hubs connected to the plate, that shaft being associated with a second set of hubs connected to a support that may be the backrest itself of the chair or easy chair on which the self-adjustable backrest is going to be used, in which case it will be referred to as pre-existing backrest, or it may be a fixed backrest which forms part of the device, in which case it will be referred to as backrest of the device. The device may include fixing elements to prevent its movement, such as legs, pegs, or a flap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application that claimspriority from and the benefit of U.S. application Ser. No. 15/778,316filed on May 23, 2018, which is a 371 of International PCT/ES2016/07083filed on Nov. 21, 2016, which claims priority from and the benefit ofSpanish Application Nos. U201631384 filed on Nov. 21, 2016 andU201531301 filed on Nov. 23, 2015.

The foregoing applications, and all documents cited therein or duringtheir prosecution (“appln cited documents”) and all documents cited orreferenced in the appln cited documents, and all documents cited orreferenced herein (“herein cited documents”), and all documents cited orreferenced in herein cited documents, together with any manufacturer'sinstructions, descriptions, product specifications, and product sheetsfor any products mentioned herein or in any document incorporated byreference herein, are hereby incorporated herein by reference, and maybe employed in the practice of the invention. More specifically, allreferenced documents are incorporated by reference to the same extent asif each individual document was specifically and individually indicatedto be incorporated by reference.

TECHNICAL FIELD

The present invention relates to a self-adjustable backrest device,which has an automatic means of position adaptation for the user'scomfort. It is applicable to any type of chairs seats that have in itsback at least a support preferably comprising vertical bars as forexample wheel chairs or some geriatric chairs.

STATE OF THE ART

For the manufacture of vehicle, office or of any other type of seats,more or less complex systems are applied so the backrest adapts to theuser's position.

Thus, for example, patent ES2118081T3 refers to a chair comprising aseat and backrest connected to each other, characterized in that thebackrest presents certain movement in being associated with twohorizontal shafts, one on which it swivels, and another that limits itsmovement.

Patent US2005035636A1 discloses a chair of the type comprising a seatand backrest connected to each other, being self-adjustable,characterized by comprising a backrest formed by back-support plate,supported by a horizontal shaft joint provided on a support, such jointbeing at a certain distance from the base of the backrest, preferably inan area at an average height of the backrest, and has a rotation springcushioned and limited by a rotation limit system, and when the plate isin resting position, it is in an approximately vertical position. Theplate, the support and the joint are included in a semi-rigid casing.

None of the cited patents provides lumbar support.

Patent WO9427472A1 describes a chair comprising a seat and backrestconnected to each other characterized by comprising a backrest/backsupport plate, supported by a horizontal shaft joint.

Patent ES2255466A1 refers to a self-adjustable chair characterized inthat it comprises a continuous single piece that serves as backrest andseat and is supported by a joint.

Patent U.S. Pat. No. 6,435,615B1 discloses a chair comprising a seat andbackrest connected to each other, characterized in that the backrest issupported by a horizontal shaft joint.

Patent DE20113075U1 refers to a chair, which comprises seat andbackrest, characterized in that the backrest comprises an arm with twoshafts, a lower one that associates it with the seat and another upperone that regulates the position of the plate on which the user rests.

None of these patents refer to an independent backrest that can becoupled to different chairs.

Patent US2005168044A1 describes a seat backrest that has a lowerextensions suitable to be pushed into the ground, such as at the beach,and serves as backrest for users sitting on the ground.

Patent WO0117398A1 discloses a self-adjustable seat that is supported onthe ground with an adaptation system not comprising a horizontal shaft.

None of the patents cited refer to an independent backrest, suitable tobe installed in any type of chair, easy chair, armchair, or even on thefloor itself that protects the lumbar area regardless of the postureadopted by the user and which lifts the buttocks relaxing the pressurethereon.

BRIEF EXPLANATION OF THE INVENTION

The invention relates to a self-adjustable backrest device, whichprotects the lumbar area and relaxes the pressure on the buttocks.

The backrest is self-adjustable, which means that it needs no control orcommand.

The device referred to supplements a seat surface such that the seatsurface exists previously and what is covered by the object of thisinvention is that it adds a backrest.

The self-adjustable backrest assembly comprises a mobile plate on whichthe user rests, wherein said plate swivels on a horizontal shaft thatpasses through a first set of hubs connected to the plate, that shaftbeing associated with a second set of hubs connected to a support thatpreferably comprises two vertical bars at its sides and accessoryelements to removably fix the second set of hubs to that support

The second set of hubs is adjustable in height and thus, heightvariation of the set of hubs will vary the height at which the plate islocated and swivels.

Hub refers herein to any element that serves as support to the shaftallowing its rotation.

The mobile plate may have different dimensions and it can comprise morethan one element. he plate has an initial position, in the absence offorces applied by the user or at his or her will, and a balancing runthat can be limited by a maximum position and a minimum position.

The ideal initial or resting position is preferably close to thevertical line although that can vary depending on the angle of thesupport. This resting position is obtained thanks to the action of arotation spring in the resting position of which the mobile plate is inan approximately vertical position where said rotation spring can becushioned for user comfort.

While not being used, the mobile plate is forced into the restingposition by the rotation spring, which is capable of overcoming theweight of the plate and bringing it to the initial position and holdingit in that position, but allowing it to yield under the pressure exertedby the user when sitting down without the user perceiving an ejectionforce.

Optionally, the run of the plate can have a stop, to limit the movementof the mobile plate.

The assembly comprising the plate, the first and second set of hubs, theshaft and the support is suitable to be associated with a chair or maybe the support pre-exists as a part of the chair, for example in thecase of a wheel chair or some geriatric chairs.

Once the self-adjustable backrest device has been installed, the userwill sit on a seat surface, that is approximately horizontal andpre-existing, and will support the back on the self-adjustable backrestdevice.

Preferably, the height of the shaft will be adjustable and will bearranged at between 12 and 33 cm above the user's seat surface, andpreferably between 18 and 27 cm.

The seat device may have armrests or any other element without alteringthe nature of the invention. Also, the plate may have a curvature,cushioning, flexibility, rigidity, or any other measure to increase usercomfort.

Lastly, the material will be wood, plywood, plastic, metal, fabric,wicker, or any other.

The plate may be separated from the shaft to facilitate the tasks ofcleaning, repair, or adjustment, among others.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, the following figures areincluded.

FIG. 1 shows the invention and shows also a part of a human body. Thechair where the device is used has two side bars (one of them is shown)and the backrest claimed is fixed to the support, in this case a pair ofbars one of them is shown. In FIG. 1 is shown one of the bars (5), themobile plate (1), the second set of hubs (4) fixed to the support, inthis case two bars, a fixing part (9), the rotation spring (8) The seatsurface (10), in this case a chair, is also shown. It is also shown astop (11) that limits the movement of the plate

FIG. 2 shows the bar (5) the mobile plate (1), the first set of hubs(2), the shaft (3), the second set of hubs (4) and the rotation spring(8) in this case shown separately exploded from the shaft. It is alsoshown in FIG. 2 the fixing zone (9) in this case fixed to the bar (5).

FIG. 3 shows, from above, the mobile plate (1), the first set of hubs(2) fixed to the mobile plate, the shaft (3), the second set of hubs(4), the rotation spring (8) connected to the second set of hubs, thefixing zone (9) suitable for fixing to the bar, not shown in thisfigure.

EMBODIMENTS OF THE INVENTION

Briefly described hereunder is an embodiment of the invention, by way ofexample and without limiting the scope thereof.

The self-adjustable backrest that supplements a seat surface.

A mobile plate (1) having a sufficient size to cover the user's backfrom the coccyx to the area of the shoulder blades.

A horizontal shaft (3) on which the aforementioned mobile plate swivels,the said shaft being supported by a first set of hubs (2) connected tothe mobile plate and a second set of hubs (4) connected to the support,in this case two bars (5), beside the mobile plate so that the mobileplate is between those two bars.

A rotation spring (8) that is connected to the second set of hubsengages the shaft so that it keeps the mobile plate (1) in anapproximately vertical position when it is in a resting position, i.e.,when there is no external force acting thereupon.

The first set of hubs (2) is connected to the mobile plate. The shaft(3) is also associated with the second set of hubs (4) that areconnected to the fixing zone (9) suitable for removably fixing to asupport.

The second set of hubs is height-adjustable, and, by varying its height,the height of the plate and the shaft are modified in relation to theseat surface (10).

The shaft on which the plate swivels is located at a height of 23 cm,the normal height being between 12 and 33 cm from the seat surface and,preferably between 18 and 27 cm

The action of the first and second set of hubs, and the horizontal shaftassociating them, allows the mobile plate to swivel such that thegreater the force exerted by the user on the upper part of the mobileplate, the greater the action on the lumbar area, reducing the pressureon the buttocks being lifted.

A stop (11) limits the movement of the mobile plate (1).

1. A self-adjustable backrest device to supplement a seat surface, thebackrest device comprising: a mobile plate (1), a first set of hubs (2)connected to the mobile plate, a second set of hubs (4) removablyconnected to a support (9), and a horizontal shaft (3) connected to thefirst set of hubs, supported by the second set of hubs and engaging arotation spring (8) so that the mobile plate is pivotable with respectto the second set of hubs, wherein the horizontal shaft is disposed at adistance from the seat surface (10) of between 12 and 33 cm.
 2. Theself-adjustable backrest device according to claim 1, wherein therotation spring, preferably cushioned, is disposed in a resting positionwhere the mobile plate (1) is disposed in an approximately verticalposition.
 3. The self-adjustable backrest device according to claim 1,further comprising a stop (11) for limiting the movement of the mobileplate.
 4. The self-adjustable backrest device according to claim 1,wherein the second set of hubs is adjustable in height along thesupport.
 5. The self-adjustable backrest device according to claim 1,wherein the mobile plate includes more than one element.
 6. Theself-adjustable backrest device according to claim 1, wherein thedistance from the seat surface is between 18 and 27 cm.